1
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cmd/7g: enable peephole optimizer

Based on cmd/9g/peep.go.

Go 1 benchmark comparison:
benchmark                          old ns/op       new ns/op       delta
BenchmarkBinaryTree17              24328574000     18351639000     -24.57%
BenchmarkFannkuch11                17029365000     10817758000     -36.48%
BenchmarkFmtFprintfEmpty           291             223             -23.37%
BenchmarkFmtFprintfString          1073            799             -25.54%
BenchmarkFmtFprintfInt             1024            778             -24.02%
BenchmarkFmtFprintfIntInt          1654            1277            -22.79%
BenchmarkFmtFprintfPrefixedInt     1360            1083            -20.37%
BenchmarkFmtFprintfFloat           2272            1415            -37.72%
BenchmarkFmtManyArgs               5933            4742            -20.07%
BenchmarkGobDecode                 53166003        38584736        -27.43%
BenchmarkGobEncode                 37930156        30074874        -20.71%
BenchmarkGzip                      1880638900      1286832100      -31.57%
BenchmarkGunzip                    386343633       292194480       -24.37%
BenchmarkHTTPClientServer          237077          179776          -24.17%
BenchmarkJSONEncode                101731690       73116925        -28.13%
BenchmarkJSONDecode                344655360       241277600       -29.99%
BenchmarkMandelbrot200             28329778        12950809        -54.29%
BenchmarkGoParse                   21670755        16554244        -23.61%
BenchmarkRegexpMatchEasy0_32       557             484             -13.11%
BenchmarkRegexpMatchEasy0_1K       4687            4832            +3.09%
BenchmarkRegexpMatchEasy1_32       539             483             -10.39%
BenchmarkRegexpMatchEasy1_1K       5100            5080            -0.39%
BenchmarkRegexpMatchMedium_32      796             651             -18.22%
BenchmarkRegexpMatchMedium_1K      233099          182047          -21.90%
BenchmarkRegexpMatchHard_32        13202           9897            -25.03%
BenchmarkRegexpMatchHard_1K        401027          303602          -24.29%
BenchmarkRevcomp                   3837679666      2816546600      -26.61%
BenchmarkTemplate                  440608300       324831040       -26.28%
BenchmarkTimeParse                 1460            1019            -30.21%
BenchmarkTimeFormat                1609            1174            -27.04%

benchmark                         old MB/s     new MB/s     speedup
BenchmarkGobDecode                14.44        19.89        1.38x
BenchmarkGobEncode                20.24        25.52        1.26x
BenchmarkGzip                     10.32        15.08        1.46x
BenchmarkGunzip                   50.23        66.41        1.32x
BenchmarkJSONEncode               19.07        26.54        1.39x
BenchmarkJSONDecode               5.63         8.04         1.43x
BenchmarkGoParse                  2.67         3.50         1.31x
BenchmarkRegexpMatchEasy0_32      57.38        66.05        1.15x
BenchmarkRegexpMatchEasy0_1K      218.47       211.91       0.97x
BenchmarkRegexpMatchEasy1_32      59.29        66.21        1.12x
BenchmarkRegexpMatchEasy1_1K      200.76       201.54       1.00x
BenchmarkRegexpMatchMedium_32     1.26         1.53         1.21x
BenchmarkRegexpMatchMedium_1K     4.39         5.62         1.28x
BenchmarkRegexpMatchHard_32       2.42         3.23         1.33x
BenchmarkRegexpMatchHard_1K       2.55         3.37         1.32x
BenchmarkRevcomp                  66.23        90.24        1.36x
BenchmarkTemplate                 4.40         5.97         1.36x

Fixes #10105.

Change-Id: I353cc9fdf922e431821508c9dbbe4d9a85d64bd4
Signed-off-by: Shenghou Ma <minux@golang.org>
Reviewed-on: https://go-review.googlesource.com/8471
Reviewed-by: Dave Cheney <dave@cheney.net>
This commit is contained in:
Shenghou Ma 2015-04-04 01:24:36 -04:00 committed by Minux Ma
parent 84b690fee1
commit 63d72f6901
2 changed files with 692 additions and 4 deletions

View File

@ -40,7 +40,102 @@ import (
var gactive uint32
func peep(firstp *obj.Prog) {
// TODO(aram)
g := (*gc.Graph)(gc.Flowstart(firstp, nil))
if g == nil {
return
}
gactive = 0
var p *obj.Prog
var r *gc.Flow
var t int
loop1:
if gc.Debug['P'] != 0 && gc.Debug['v'] != 0 {
gc.Dumpit("loop1", g.Start, 0)
}
t = 0
for r = g.Start; r != nil; r = r.Link {
p = r.Prog
// TODO(minux) Handle smaller moves. arm and amd64
// distinguish between moves that *must* sign/zero
// extend and moves that don't care so they
// can eliminate moves that don't care without
// breaking moves that do care. This might let us
// simplify or remove the next peep loop, too.
if p.As == arm64.AMOVD || p.As == arm64.AFMOVD {
if regtyp(&p.To) {
// Try to eliminate reg->reg moves
if regtyp(&p.From) {
if p.From.Type == p.To.Type {
if copyprop(r) {
excise(r)
t++
} else if subprop(r) && copyprop(r) {
excise(r)
t++
}
}
}
}
}
}
if t != 0 {
goto loop1
}
/*
* look for MOVB x,R; MOVB R,R (for small MOVs not handled above)
*/
var p1 *obj.Prog
var r1 *gc.Flow
for r := (*gc.Flow)(g.Start); r != nil; r = r.Link {
p = r.Prog
switch p.As {
default:
continue
case arm64.AMOVH,
arm64.AMOVHU,
arm64.AMOVB,
arm64.AMOVBU,
arm64.AMOVW,
arm64.AMOVWU:
if p.To.Type != obj.TYPE_REG {
continue
}
}
r1 = r.Link
if r1 == nil {
continue
}
p1 = r1.Prog
if p1.As != p.As {
continue
}
if p1.From.Type != obj.TYPE_REG || p1.From.Reg != p.To.Reg {
continue
}
if p1.To.Type != obj.TYPE_REG || p1.To.Reg != p.To.Reg {
continue
}
excise(r1)
}
if gc.Debug['D'] > 1 {
goto ret /* allow following code improvement to be suppressed */
}
/* TODO(minux):
* look for OP x,y,R; CMP R, $0 -> OP.S x,y,R
* when OP can set condition codes correctly
*/
ret:
gc.Flowend(g)
}
func excise(r *gc.Flow) {
@ -57,6 +152,599 @@ func regtyp(a *obj.Addr) bool {
return a.Type == obj.TYPE_REG && arm64.REG_R0 <= a.Reg && a.Reg <= arm64.REG_F31 && a.Reg != arm64.REGZERO
}
/*
* the idea is to substitute
* one register for another
* from one MOV to another
* MOV a, R1
* ADD b, R1 / no use of R2
* MOV R1, R2
* would be converted to
* MOV a, R2
* ADD b, R2
* MOV R2, R1
* hopefully, then the former or latter MOV
* will be eliminated by copy propagation.
*
* r0 (the argument, not the register) is the MOV at the end of the
* above sequences. This returns 1 if it modified any instructions.
*/
func subprop(r0 *gc.Flow) bool {
p := (*obj.Prog)(r0.Prog)
v1 := (*obj.Addr)(&p.From)
if !regtyp(v1) {
return false
}
v2 := (*obj.Addr)(&p.To)
if !regtyp(v2) {
return false
}
for r := gc.Uniqp(r0); r != nil; r = gc.Uniqp(r) {
if gc.Uniqs(r) == nil {
break
}
p = r.Prog
if p.As == obj.AVARDEF || p.As == obj.AVARKILL {
continue
}
if p.Info.Flags&gc.Call != 0 {
return false
}
if p.Info.Flags&(gc.RightRead|gc.RightWrite) == gc.RightWrite {
if p.To.Type == v1.Type {
if p.To.Reg == v1.Reg {
copysub(&p.To, v1, v2, 1)
if gc.Debug['P'] != 0 {
fmt.Printf("gotit: %v->%v\n%v", gc.Ctxt.Dconv(v1), gc.Ctxt.Dconv(v2), r.Prog)
if p.From.Type == v2.Type {
fmt.Printf(" excise")
}
fmt.Printf("\n")
}
for r = gc.Uniqs(r); r != r0; r = gc.Uniqs(r) {
p = r.Prog
copysub(&p.From, v1, v2, 1)
copysub1(p, v1, v2, 1)
copysub(&p.To, v1, v2, 1)
if gc.Debug['P'] != 0 {
fmt.Printf("%v\n", r.Prog)
}
}
t := int(int(v1.Reg))
v1.Reg = v2.Reg
v2.Reg = int16(t)
if gc.Debug['P'] != 0 {
fmt.Printf("%v last\n", r.Prog)
}
return true
}
}
}
if copyau(&p.From, v2) || copyau1(p, v2) || copyau(&p.To, v2) {
break
}
if copysub(&p.From, v1, v2, 0) != 0 || copysub1(p, v1, v2, 0) != 0 || copysub(&p.To, v1, v2, 0) != 0 {
break
}
}
return false
}
/*
* The idea is to remove redundant copies.
* v1->v2 F=0
* (use v2 s/v2/v1/)*
* set v1 F=1
* use v2 return fail (v1->v2 move must remain)
* -----------------
* v1->v2 F=0
* (use v2 s/v2/v1/)*
* set v1 F=1
* set v2 return success (caller can remove v1->v2 move)
*/
func copyprop(r0 *gc.Flow) bool {
p := (*obj.Prog)(r0.Prog)
v1 := (*obj.Addr)(&p.From)
v2 := (*obj.Addr)(&p.To)
if copyas(v1, v2) {
if gc.Debug['P'] != 0 {
fmt.Printf("eliminating self-move\n", r0.Prog)
}
return true
}
gactive++
if gc.Debug['P'] != 0 {
fmt.Printf("trying to eliminate %v->%v move from:\n%v\n", gc.Ctxt.Dconv(v1), gc.Ctxt.Dconv(v2), r0.Prog)
}
return copy1(v1, v2, r0.S1, 0)
}
// copy1 replaces uses of v2 with v1 starting at r and returns 1 if
// all uses were rewritten.
func copy1(v1 *obj.Addr, v2 *obj.Addr, r *gc.Flow, f int) bool {
if uint32(r.Active) == gactive {
if gc.Debug['P'] != 0 {
fmt.Printf("act set; return 1\n")
}
return true
}
r.Active = int32(gactive)
if gc.Debug['P'] != 0 {
fmt.Printf("copy1 replace %v with %v f=%d\n", gc.Ctxt.Dconv(v2), gc.Ctxt.Dconv(v1), f)
}
var t int
var p *obj.Prog
for ; r != nil; r = r.S1 {
p = r.Prog
if gc.Debug['P'] != 0 {
fmt.Printf("%v", p)
}
if f == 0 && gc.Uniqp(r) == nil {
// Multiple predecessors; conservatively
// assume v1 was set on other path
f = 1
if gc.Debug['P'] != 0 {
fmt.Printf("; merge; f=%d", f)
}
}
t = copyu(p, v2, nil)
switch t {
case 2: /* rar, can't split */
if gc.Debug['P'] != 0 {
fmt.Printf("; %v rar; return 0\n", gc.Ctxt.Dconv(v2))
}
return false
case 3: /* set */
if gc.Debug['P'] != 0 {
fmt.Printf("; %v set; return 1\n", gc.Ctxt.Dconv(v2))
}
return true
case 1, /* used, substitute */
4: /* use and set */
if f != 0 {
if gc.Debug['P'] == 0 {
return false
}
if t == 4 {
fmt.Printf("; %v used+set and f=%d; return 0\n", gc.Ctxt.Dconv(v2), f)
} else {
fmt.Printf("; %v used and f=%d; return 0\n", gc.Ctxt.Dconv(v2), f)
}
return false
}
if copyu(p, v2, v1) != 0 {
if gc.Debug['P'] != 0 {
fmt.Printf("; sub fail; return 0\n")
}
return false
}
if gc.Debug['P'] != 0 {
fmt.Printf("; sub %v->%v\n => %v", gc.Ctxt.Dconv(v2), gc.Ctxt.Dconv(v1), p)
}
if t == 4 {
if gc.Debug['P'] != 0 {
fmt.Printf("; %v used+set; return 1\n", gc.Ctxt.Dconv(v2))
}
return true
}
}
if f == 0 {
t = copyu(p, v1, nil)
if f == 0 && (t == 2 || t == 3 || t == 4) {
f = 1
if gc.Debug['P'] != 0 {
fmt.Printf("; %v set and !f; f=%d", gc.Ctxt.Dconv(v1), f)
}
}
}
if gc.Debug['P'] != 0 {
fmt.Printf("\n")
}
if r.S2 != nil {
if !copy1(v1, v2, r.S2, f) {
return false
}
}
}
return true
}
// If s==nil, copyu returns the set/use of v in p; otherwise, it
// modifies p to replace reads of v with reads of s and returns 0 for
// success or non-zero for failure.
//
// If s==nil, copy returns one of the following values:
// 1 if v only used
// 2 if v is set and used in one address (read-alter-rewrite;
// can't substitute)
// 3 if v is only set
// 4 if v is set in one address and used in another (so addresses
// can be rewritten independently)
// 0 otherwise (not touched)
func copyu(p *obj.Prog, v *obj.Addr, s *obj.Addr) int {
if p.From3.Type != obj.TYPE_NONE {
// 7g never generates a from3
fmt.Printf("copyu: from3 (%v) not implemented\n", gc.Ctxt.Dconv(&p.From3))
}
if p.To2.Type != obj.TYPE_NONE {
// 7g never generates a to2
fmt.Printf("copyu: to2 (%v) not implemented\n", gc.Ctxt.Dconv(&p.To2))
}
switch p.As {
default:
fmt.Printf("copyu: can't find %v\n", obj.Aconv(int(p.As)))
return 2
case obj.ANOP, /* read p->from, write p->to */
arm64.ANEG,
arm64.AFNEGD,
arm64.AFNEGS,
arm64.AFSQRTD,
arm64.AFCVTZSD,
arm64.AFCVTZSS,
arm64.AFCVTZSDW,
arm64.AFCVTZSSW,
arm64.AFCVTZUD,
arm64.AFCVTZUS,
arm64.AFCVTZUDW,
arm64.AFCVTZUSW,
arm64.AFCVTSD,
arm64.AFCVTDS,
arm64.ASCVTFD,
arm64.ASCVTFS,
arm64.ASCVTFWD,
arm64.ASCVTFWS,
arm64.AUCVTFD,
arm64.AUCVTFS,
arm64.AUCVTFWD,
arm64.AUCVTFWS,
arm64.AMOVB,
arm64.AMOVBU,
arm64.AMOVH,
arm64.AMOVHU,
arm64.AMOVW,
arm64.AMOVWU,
arm64.AMOVD,
arm64.AFMOVS,
arm64.AFMOVD:
if p.Scond == 0 {
if s != nil {
if copysub(&p.From, v, s, 1) != 0 {
return 1
}
// Update only indirect uses of v in p->to
if !copyas(&p.To, v) {
if copysub(&p.To, v, s, 1) != 0 {
return 1
}
}
return 0
}
if copyas(&p.To, v) {
// Fix up implicit from
if p.From.Type == obj.TYPE_NONE {
p.From = p.To
}
if copyau(&p.From, v) {
return 4
}
return 3
}
if copyau(&p.From, v) {
return 1
}
if copyau(&p.To, v) {
// p->to only indirectly uses v
return 1
}
return 0
}
/* rar p->from, write p->to or read p->from, rar p->to */
if p.From.Type == obj.TYPE_MEM {
if copyas(&p.From, v) {
// No s!=nil check; need to fail
// anyway in that case
return 2
}
if s != nil {
if copysub(&p.To, v, s, 1) != 0 {
return 1
}
return 0
}
if copyas(&p.To, v) {
return 3
}
} else if p.To.Type == obj.TYPE_MEM {
if copyas(&p.To, v) {
return 2
}
if s != nil {
if copysub(&p.From, v, s, 1) != 0 {
return 1
}
return 0
}
if copyau(&p.From, v) {
return 1
}
} else {
fmt.Printf("copyu: bad %v\n", p)
}
return 0
case arm64.AADD, /* read p->from, read p->reg, write p->to */
arm64.ASUB,
arm64.AAND,
arm64.AORR,
arm64.AEOR,
arm64.AMUL,
arm64.ASMULL,
arm64.AUMULL,
arm64.ASMULH,
arm64.AUMULH,
arm64.ASDIV,
arm64.AUDIV,
arm64.ALSL,
arm64.ALSR,
arm64.AASR,
arm64.AFADDD,
arm64.AFADDS,
arm64.AFSUBD,
arm64.AFSUBS,
arm64.AFMULD,
arm64.AFMULS,
arm64.AFDIVD,
arm64.AFDIVS:
if s != nil {
if copysub(&p.From, v, s, 1) != 0 {
return 1
}
if copysub1(p, v, s, 1) != 0 {
return 1
}
// Update only indirect uses of v in p->to
if !copyas(&p.To, v) {
if copysub(&p.To, v, s, 1) != 0 {
return 1
}
}
return 0
}
if copyas(&p.To, v) {
if p.Reg == 0 {
// Fix up implicit reg (e.g., ADD
// R3,R4 -> ADD R3,R4,R4) so we can
// update reg and to separately.
p.Reg = p.To.Reg
}
if copyau(&p.From, v) {
return 4
}
if copyau1(p, v) {
return 4
}
return 3
}
if copyau(&p.From, v) {
return 1
}
if copyau1(p, v) {
return 1
}
if copyau(&p.To, v) {
return 1
}
return 0
case arm64.ABEQ,
arm64.ABNE,
arm64.ABGE,
arm64.ABLT,
arm64.ABGT,
arm64.ABLE,
arm64.ABLO,
arm64.ABLS,
arm64.ABHI,
arm64.ABHS:
return 0
case obj.ACHECKNIL, /* read p->from */
arm64.ACMP, /* read p->from, read p->reg */
arm64.AFCMPD,
arm64.AFCMPS:
if s != nil {
if copysub(&p.From, v, s, 1) != 0 {
return 1
}
return copysub1(p, v, s, 1)
}
if copyau(&p.From, v) {
return 1
}
if copyau1(p, v) {
return 1
}
return 0
case arm64.AB: /* read p->to */
if s != nil {
if copysub(&p.To, v, s, 1) != 0 {
return 1
}
return 0
}
if copyau(&p.To, v) {
return 1
}
return 0
case obj.ARET: /* funny */
if s != nil {
return 0
}
// All registers die at this point, so claim
// everything is set (and not used).
return 3
case arm64.ABL: /* funny */
if p.From.Type == obj.TYPE_REG && v.Type == obj.TYPE_REG && p.From.Reg == v.Reg {
return 2
}
if s != nil {
if copysub(&p.To, v, s, 1) != 0 {
return 1
}
return 0
}
if copyau(&p.To, v) {
return 4
}
return 3
// R31 is zero, used by DUFFZERO, cannot be substituted.
// R16 is ptr to memory, used and set, cannot be substituted.
case obj.ADUFFZERO:
if v.Type == obj.TYPE_REG {
if v.Reg == 31 {
return 1
}
if v.Reg == 16 {
return 2
}
}
return 0
// R16, R17 are ptr to src, dst, used and set, cannot be substituted.
// R27 is scratch, set by DUFFCOPY, cannot be substituted.
case obj.ADUFFCOPY:
if v.Type == obj.TYPE_REG {
if v.Reg == 16 || v.Reg == 17 {
return 2
}
if v.Reg == 27 {
return 3
}
}
return 0
case arm64.AHINT,
obj.ATEXT,
obj.APCDATA,
obj.AFUNCDATA,
obj.AVARDEF,
obj.AVARKILL:
return 0
}
}
// copyas returns 1 if a and v address the same register.
//
// If a is the from operand, this means this operation reads the
// register in v. If a is the to operand, this means this operation
// writes the register in v.
func copyas(a *obj.Addr, v *obj.Addr) bool {
if regtyp(v) {
if a.Type == v.Type {
if a.Reg == v.Reg {
return true
}
}
}
return false
}
// copyau returns 1 if a either directly or indirectly addresses the
// same register as v.
//
// If a is the from operand, this means this operation reads the
// register in v. If a is the to operand, this means the operation
// either reads or writes the register in v (if !copyas(a, v), then
// the operation reads the register in v).
func copyau(a *obj.Addr, v *obj.Addr) bool {
if copyas(a, v) {
return true
}
if v.Type == obj.TYPE_REG {
if a.Type == obj.TYPE_MEM || (a.Type == obj.TYPE_ADDR && a.Reg != 0) {
if v.Reg == a.Reg {
return true
}
}
}
return false
}
// copyau1 returns 1 if p->reg references the same register as v and v
// is a direct reference.
func copyau1(p *obj.Prog, v *obj.Addr) bool {
if regtyp(v) && v.Reg != 0 {
if p.Reg == v.Reg {
return true
}
}
return false
}
// copysub replaces v with s in a if f!=0 or indicates it if could if f==0.
// Returns 1 on failure to substitute (it always succeeds on arm64).
func copysub(a *obj.Addr, v *obj.Addr, s *obj.Addr, f int) int {
if f != 0 {
if copyau(a, v) {
a.Reg = s.Reg
}
}
return 0
}
// copysub1 replaces v with s in p1->reg if f!=0 or indicates if it could if f==0.
// Returns 1 on failure to substitute (it always succeeds on arm64).
func copysub1(p1 *obj.Prog, v *obj.Addr, s *obj.Addr, f int) int {
if f != 0 {
if copyau1(p1, v) {
p1.Reg = s.Reg
}
}
return 0
}
func sameaddr(a *obj.Addr, v *obj.Addr) bool {
if a.Type != v.Type {
return false

View File

@ -1,7 +1,7 @@
// errorcheck -0 -d=nil
// Fails on ppc64x and arm64 because of incomplete optimization.
// See issues 9058 and 10105.
// +build !ppc64,!ppc64le,!arm64
// Fails on ppc64x because of incomplete optimization.
// See issues 9058.
// +build !ppc64,!ppc64le
// Copyright 2013 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style